#Question id: 2441
#Unit 2. Cellular Organization
Which of the following statement(s) is (are) true of microtubule assembly?
a. GDP-tubulin normally assembles into microtubules.
b. Microtubule (-) ends grow faster than microtubule (+) ends.
c. Tubulin subunits assemble to form a protofilament.
d. Microtubules consist of multiple protofilaments.
e. Microtubules with a GTP cap will shorten.
#Question id: 5679
#Unit 5. Developmental Biology
Following statements regarding to the molecular processes of capacitation.
A. The sperm cell membrane is altered by the removal of albumin by cholesterol in the female reproductive tract.
B. Particular proteins or carbohydrates on the sperm surface are lost during decapacitation.
C. The membrane potential of the sperm cell becomes more positive as potassium ions leave the sperm. This change in membrane potential may allow calcium channels to be opened and permit calcium to enter the sperm.
D. Calcium and bicarbonate ions are critical in activating cAMP production and in facilitating the membrane fusion events of the acrosome reaction.
E. As a result of cAMP formation, protein phosphorylation occurs. Once they are phosphorylated, some proteins migrate to the surface of the sperm head. One of these proteins is izumo, which is critical in sperm-egg fusion.
which one of the following combinations is correct?
#Question id: 2686
#Unit 2. Cellular Organization
Enzyme which can break and seal the DNA strand
#Question id: 18762
#Unit 13. Methods in Biology
#Question id: 7074
#Unit 5. Developmental Biology
The left-right axis decided by the paracrine factor ____a___ and the transcription factor___b_____ expressed in ____c_____ side.